/*

This file is part of Ext JS 4

Copyright (c) 2011 Sencha Inc

Contact:  http://www.sencha.com/contact

Commercial Usage
Licensees holding valid commercial licenses may use this file in accordance with the Commercial Software License Agreement provided with the Software or, alternatively, in accordance with the terms contained in a written agreement between you and Sencha.

If you are unsure which license is appropriate for your use, please contact the sales department at http://www.sencha.com/contact.

*/
/**
 * @class Ext.util.Filter
 * @extends Object
 * <p>Represents a filter that can be applied to a {@link Ext.util.MixedCollection MixedCollection}. Can either simply
 * filter on a property/value pair or pass in a filter function with custom logic. Filters are always used in the context
 * of MixedCollections, though {@link Ext.data.Store Store}s frequently create them when filtering and searching on their
 * records. Example usage:</p>
<pre><code>
//set up a fictional MixedCollection containing a few people to filter on
var allNames = new Ext.util.MixedCollection();
allNames.addAll([
    {id: 1, name: 'Ed',    age: 25},
    {id: 2, name: 'Jamie', age: 37},
    {id: 3, name: 'Abe',   age: 32},
    {id: 4, name: 'Aaron', age: 26},
    {id: 5, name: 'David', age: 32}
]);

var ageFilter = new Ext.util.Filter({
    property: 'age',
    value   : 32
});

var longNameFilter = new Ext.util.Filter({
    filterFn: function(item) {
        return item.name.length > 4;
    }
});

//a new MixedCollection with the 3 names longer than 4 characters
var longNames = allNames.filter(longNameFilter);

//a new MixedCollection with the 2 people of age 24:
var youngFolk = allNames.filter(ageFilter);
</code></pre>
 */
Ext.define('Ext.util.Filter', {

    /* Begin Definitions */

    /* End Definitions */
    /**
     * @cfg {String} property The property to filter on. Required unless a {@link #filterFn} is passed
     */
    
    /**
     * @cfg {Function} filterFn A custom filter function which is passed each item in the {@link Ext.util.MixedCollection} 
     * in turn. Should return true to accept each item or false to reject it
     */
    
    /**
     * @cfg {Boolean} anyMatch True to allow any match - no regex start/end line anchors will be added. Defaults to false
     */
    anyMatch: false,
    
    /**
     * @cfg {Boolean} exactMatch True to force exact match (^ and $ characters added to the regex). Defaults to false.
     * Ignored if anyMatch is true.
     */
    exactMatch: false,
    
    /**
     * @cfg {Boolean} caseSensitive True to make the regex case sensitive (adds 'i' switch to regex). Defaults to false.
     */
    caseSensitive: false,
    
    /**
     * @cfg {String} root Optional root property. This is mostly useful when filtering a Store, in which case we set the
     * root to 'data' to make the filter pull the {@link #property} out of the data object of each item
     */

    /**
     * Creates new Filter.
     * @param {Object} config (optional) Config object
     */
    constructor: function(config) {
        Ext.apply(this, config);
        
        //we're aliasing filter to filterFn mostly for API cleanliness reasons, despite the fact it dirties the code here.
        //Ext.util.Sorter takes a sorterFn property but allows .sort to be called - we do the same here
        this.filter = this.filter || this.filterFn;
        
        if (this.filter == undefined) {
            if (this.property == undefined || this.value == undefined) {
                // Commented this out temporarily because it stops us using string ids in models. TODO: Remove this once
                // Model has been updated to allow string ids
                
                // Ext.Error.raise("A Filter requires either a property or a filterFn to be set");
            } else {
                this.filter = this.createFilterFn();
            }
            
            this.filterFn = this.filter;
        }
    },
    
    /**
     * @private
     * Creates a filter function for the configured property/value/anyMatch/caseSensitive options for this Filter
     */
    createFilterFn: function() {
        var me       = this,
            matcher  = me.createValueMatcher(),
            property = me.property;
        
        return function(item) {
            return matcher.test(me.getRoot.call(me, item)[property]);
        };
    },
    
    /**
     * @private
     * Returns the root property of the given item, based on the configured {@link #root} property
     * @param {Object} item The item
     * @return {Object} The root property of the object
     */
    getRoot: function(item) {
        return this.root == undefined ? item : item[this.root];
    },
    
    /**
     * @private
     * Returns a regular expression based on the given value and matching options
     */
    createValueMatcher : function() {
        var me            = this,
            value         = me.value,
            anyMatch      = me.anyMatch,
            exactMatch    = me.exactMatch,
            caseSensitive = me.caseSensitive,
            escapeRe      = Ext.String.escapeRegex;
        
        if (!value.exec) { // not a regex
            value = String(value);

            if (anyMatch === true) {
                value = escapeRe(value);
            } else {
                value = '^' + escapeRe(value);
                if (exactMatch === true) {
                    value += '$';
                }
            }
            value = new RegExp(value, caseSensitive ? '' : 'i');
         }
         
         return value;
    }
});
